Containers designed to enclose a single semiconductor wafer are already known Such containers are generally used for carrying and handling wafers, while ensuring their physical protection. These wafers can be bare, partially processed, or entirely processed and may include integrated circuits.
The containers for semiconductor wafers known in the prior art are constituted by two parts, a first disk-shaped part forming the bottom, and a second part, having a similar shape, forming the lid. In this type of container, the lid and the bottom have matching peripheral surfaces, allowing these two parts to engage one into the other. This engagement may have some clearance, that is, it may be free or slightly forced, in order to provide coupling between the lid and the bottom. This engagement can ensure locking of the lid on the bottom, particularly further to the rotation of the lid with respect to the bottom.
The shape of the bottom and lid of the containers of the prior art is always slightly different. When it is desired to put wafers in such containers, it is necessary to manufacture then to simultaneously handle two sets of parts, a first set of bottoms and a second set of lids. Since the bottoms and the lids are generally made of the same material, particularly of a plastic material, and since, on the other hand, the bottoms and lids have relatively similar shapes, it is difficult to distinguish them and inversions may occur.
Since handling operations for loading wafers in containers or unloading them are often carried out by robots, separately handling bottoms and lids complicates the robot's operation. It is also difficult for a robot to lay a lid on a bottom while accurately adjusting the relative angular position of these two parts. To carry out such an operation, the robot must localize the angular position of the bottom, localize the angular position of the lid and accordingly rotate one of these two pieces. The implementation of these relatively complex functions is liable to malfunction and requires expensive equipment.